The subject matter disclosed herein relates to a method, a system and a computer readable medium for processing a medical video image for reducing perceived noise. More particularly, the disclosed subject matter relates to image processing, and to systems and methods for location-selective medical image filtering capabilities.
Despite the emergence of powerful imaging modalities that do not use ionizing radiation, fluoroscopic X-ray systems continue to play a significant role in medical imaging, particularly for interventional procedures, where real-time imaging is very important. For pediatric patients, the consideration of lifetime radiation risk versus procedural benefit to the patient remains a fundamental consideration for the clinician. For a manufacturer of medical X-ray imaging equipment, it is critically important to exploit advances in X-ray component technologies, image processing, system design and advanced imaging techniques to provide the clinician with the appropriate imaging tools and controls to effectively perform procedures at the lowest possible total X-ray dose.
Since radiation dose has to be kept as low as reasonably achievable, quantum noise is an inherent property of fluoroscopy images. The presence of noise is disturbing for the user, making it more difficult to assess the position of interventional tools and characteristics of relevant anatomical information. It is possible to reduce noise by known image processing methods, but it is very difficult to do it without degrading medical information. Indeed, a doctor's human visual perception—utilizing a vast amount of a priori information about anatomy and tool motion—usually outperforms all algorithmic solutions to identify objects in the presence of noise. However, performing this task requires intense concentration, and in the long run it is very tiring for the doctor, and distracts his attention from the intervention he is performing.
Similar noise related problems arise in connection with other types of medical video imaging, e.g. in ultrasound techniques.
Significant efforts have been directed towards decreasing this burden on physicians, and to mitigate the disturbing noise by means of noise filtering. There are known noise filtering approaches, e.g. the so called FNR (fluoroscopic noise reduction), as described e.g. in Barry Belanger's and John Boudry's: Management of pediatric radiation dose using GE fluoroscopic equipment (Pediatr. Radiol., 2006 September; 36 (Suppl. 2) 204-211, Doi: 10.1007/s00247-006-0228-9, PMCID: PMC2663641).
However, no filtering technique is known which effectively reduces perceived noise while not degrading image quality.
Thus, there is a need for a solution allowing an improvement over existing methods and systems. There is a need for an image processing method, computer program and system eliminating as much of the shortcomings of known techniques as possible. There is a particular need for a method for processing a medical video image for reducing perceived noise while maintaining a highly informative image quality in an area of interest.
It has been recognized that the highly relevant medical information is usually focused in the center of the image perceived by the foveal vision of an interventionist, while a great part of the perceived noise is coming from the image edges, perceived by peripheral vision, which is more sensitive to temporal variations.